236 PERSONS (CASES) WITH PAST REACTIVE HUMAN IMMUNODEFICIENCY VIRUS TYPE-1 (HIV-1) EIAS and indeterminate HIV-1 Western Blots (IWBS) were followed prospectively. Of the 159 cases followed 6 months, 6 seroconverted (3.8% seroconversation risk). All 6 seroconverters reported HIV risk behaviors, all had p24 bands prior to seroconversion, and 5 of the 6 seroconverted within one month. HIV-1 culture, polymerase chain reaction, serum p24 antigen, and the recombinant assays, CBre 3 and Syva Microtrak, had specificities of 100%, 99.1%, 100%, 97.1%, and 100%, respectively. An algorithm for evaluation of persons with IWB is proposed. A case-control study demonstrated past positive tuberculin skin test, recent tetanus booster, autoantibodies, and parity were associated with IWBs. No cross-reactivity was seen with HTLV-1 or HIV-2. Cases reported significantly more anxiety than controls, due in large part to the IWB. High- risk cases reported more anxiety than low-risk cases. Informational brochures for counseling were designed.